This invention relates to coasters for holding glasses and other containers for hot and cold beverages, and more particularly to such coasters that are more effective for longer periods of time than those presently available.
Glasses and containers having cold beverages collect condensate on their outside surfaces that runs down the side of the container into the coaster or onto the furniture, or alternatively, drips from the container onto the clothes of the person lifting the container to drink. Where a cold beverage container is placed on a warmer furniture surface, the cooling of the furniture surface by the container deposits condensate from the surrounding air directly onto the surface. Where the cup or glass containing a hot beverage is placed on a cooler surface, such as furniture, the steam or condensate from the warm container is deposited directly on the furniture.
When using conventionally made coasters in an effort to collect the moisture and protect the user and the furniture, the well of the coaster progressively fills with condensed water about the base of the glass as condensate continuously forms and drips from the glass walls. This collected condensate is cold, and is maintained in its cold condition by contact with the bottom of the glass that contains melting ice cubes. Therefore the coaster itself becomes a container of cold liquid, much as the glass it is holding, and heat is therefore transferred from the furniture supporting the coaster and from the ambient air surrounding the coaster to the base and sides of the coaster. When the outside surfaces of the coaster have become chilled below the dew point of the surrounding air, moisture condenses on the surface of the coaster and drips onto the furniture. Additionally, heat is removed from the surface of the furniture itself through the base of the coaster until it also becomes chilled below the dew point, causing direct condensation onto the surface of the furniture. These conditions are experienced in almost all climates and environments, but are, of course, much more pronounced and intensified in warm, humid environments, such as are found in tropical southern regions.
An additional difficulty experienced with conventional coasters is in the base pad that is usually made of sponge, cork, plastic or fabric material and is usually disposed inside the well of the coaster to receive the bottom of the glass and collect the condensate dripping from its walls. Quite often as this base material becomes wet, a cohesive bond is formed between it and the base of the glass, resulting in the coaster or its base pad sticking to the glass as the glass is raised to drinking position. Often this temporary bond is broken as the glass is raised whereupon the coaster or its base pad then drops onto the table or onto the lap of the drinker. In some instances, this base pad or insert in the coaster is made with an uneven surface, having ridges, napped piles of fibres, or other protuberances, all of which tend to tilt and sometimes spill glasses having small bases. In other instances, the absorption of condensed water by the base pad results in unequal expansion or swelling of the pad, again resulting in the glass being tilted or its contents being spilled.